1. Field
The disclosure relates to the field of connection of optical waveguides. The disclosure relates in particular to an apparatus in order to connect ends of optical waveguides to one another by means of a thermal process. The disclosure also relates to a corresponding method.
2. Technical Background
Apparatus for connection of optical waveguides by means of the application of heat are generally known. In the case of splices such as these, the fiber ends of the optical waveguides to be spliced are heated, as a result of which they can be fused to one another. In this case, it is desirable for the resultant attenuation of the spliced connection to be as low as possible. A different amount of effort is required for this purpose, depending on the apparatus type, for example because the fiber ends to be spliced are aligned with respect to one another and the splicing process is matched to the circumstances resulting from the environment, in order to ensure that the attenuation, resulting from the spliced connection, for the light propagating in the fiber is as low as possible. By way of example, an arc, a corona discharge, a laser beam or a resistance wire in the form of a heating filament, for example, can be used to melt the fiber ends.
Recently, there has been a demand for splicers which can be produced at low cost and are as reliable during operation as possible, are simple to operate and require little maintenance in use while nevertheless complying with demands that are as stringent as possible for the quality of the resultant spliced connection. Apparatus such as these are used, for example, for installation of optical waveguides in buildings or for connection of the buildings by optical waveguides to the existing network. Apparatus such as these have characteristics including low weight, mechanical and electronic elements in the apparatus which are as simple and robust as possible, and as high a degree of automation as possible for the production of the spliced connection.
By way of example, WO 2007/019843 describes a splicer which uses electromechanical motors, for example stepping motors, for alignment of the fiber ends, as well as mechanical step-down conversion. The stepping motors and the step-down conversion are available at lost cost, although compromises must be accepted in the positioning accuracy of these mechanical elements. In the case of a splicer such as this, a residual offset generally remains when viewed in a direction at right angles to the longitudinal axis of the optical waveguides. Exact alignment of the fibers can be achieved only by chance, and a residual offset generally remains, because of the restricted accuracy of said positioning device, in the order of magnitude of approximately 1 micrometer (μm). In the case of apparatus such as these, the welding process is carried out with a fixed welding current and a fixed welding time. This setting was defined as being optimum just for one typical initial offset, as a result of which initial offset values which differ from this are not treated individually. In particular, no matching of the welding parameters is carried out.
Conventional splicers, for example as described in U.S. Pat. No. 6,230,522, use an offset reduction in order to adjust the apparatus and its splicing parameters to match a splicing environment, and retain unchanged the parameter set, which is then defined, for control of the next splicing process and further splicing processes. To this end, a defined distance is set between the fibers to be connected for a test splice, the fiber ends are heated, and any remaining residual offset of the connected fibers is determined. A relationship which indicates a current correction as a function of a remaining residual offset can be stored in the apparatus. These apparatus therefore require complex recording and alignment electronics as well as complex mechanical elements in order to always ensure that the optical waveguides are aligned with respect to one another as accurately as possible and as reproducibly as possible at the start of the normal splicing process. By way of example, complex positioning systems such as these use piezo elements based on piezoelectric ceramics, which allow the cores of the glass fibers to be welded to be positioned on two axes.
It is therefore desirable to nevertheless make it possible to produce a high-quality spliced connection using a splicer of the type mentioned initially, which can achieve only relatively inaccurate positioning of the ends of the optical waveguides.